What is the best way to clean carpet and avoid mold?

by | May 18, 2022 | Mold Advice & Tips

You may not be aware that cleaning your carpets actually has more potential dangers than vacuuming. For example, carpet technicians often use detergents, soaps, spot removers and degreasers that contain several toxic chemicals which have been proven to be harmful to you and your family’s health and also your pet’s health.

If you have carpet, your goal should be to find the best and safest cleaning method. Some methods leave toxic residues and some can actually damage and shorten the life of the carpet. Worse yet, some cleaning systems will actually create water damage and promote mold growth.

What you need to understand is that carpet is like a sponge for dirt, dust, toxins and dangerous pathogens such as parasitic mold spores to land and grow, even when there has been no significant water damage. Simple water and or milk spills can even cause mold to grow in the carpet and pad.

There is also the fact that after the carpet has been shampooed or steam cleaned, it can take anywhere from 48-36 hours to dry which is plenty of time for mold to grow.

Then when the carpet dries, everytime someone walks on the carpet, each step can cause these toxins and microorganisms like mold with their spores and mycotoxins in the carpet to become airborne. The end result is the indoor air quality of your home will become severely polluted and quite possibly, you and your family can get very sick.

In this article, I will explain the best and least toxic way to clean your carpet. But first, let me quickly go over the different methods. I will first start with the worst method and end with the best solution, which I will also include scientific studies that verify my claims.

Do It Yourself (DIY) Cleaning – DIY carpet cleaning entails renting a carpet cleaning machine from your local Home Depot, Lowes or Walmart, buying some cheap toxic shampoo and then doing the job yourself. This is the absolute most unsafe and poorest way that you can use to clean your carpet. Yes, you will save a lot of money, but the risk to you and your family’s health is not worth saving a couple hundred bucks.

The reason this is the most dangerous method is because these rented machines are not powerful enough to suck all the water, shampoo, dirt, and mold spores out of your carpet.  This will cause your carpet to remain wet for 48-36 hours or more which will cause mold to start growing. Also, it will become easily soiled again because of all the dirt and shampoo residue left behind from the weak vacuum.

Professional Shampooing – This is the oldest and least safe method to clean your carpets professionally. While you can deep clean heavily soiled carpets, toxic shampoos are often used that leave a high amount of residue and it also takes very a long time to dry.

Like the DIY method, sometimes it can take 48-36 hours for the carpet and padding to be completely dry which is plenty of time for mold to start growing. Also, it will become easily soiled again because of all the dirt and shampoo residue left behind.

Bonnet, Dry Cleaning or Carbonated Water Cleaning – This is often called “dry cleaning,” but this is a misnomer because water is used during the cleaning process.  This process uses a chemical spray cleaning solution or carbonated water to the carpet in order to allegedly bring down the PH. A rotary floor machine/scrubber with a stiff brush and or damp or dry pads goes over the carpet and the pads are used to lift the dirt from the carpet.

This method is very poor for soil removal and leaves a lot of detergent residue and dirt behind. This will cause rapid re-soiling of your carpets. Also, the scrubber may damage or destroy your carpet fibers leaving permanent swirl marks and ripped fibers.

Steam Cleaning – This is also known as hot water extraction cleaning, warm or hot water extraction. This method typically involves the use of what is called a truck (van) mount which is a powerful machine/engine that is used for extra vacuum suction power. A truck-mount is much more powerful than portable cleaning units and can clean the carpets and get it to dry much more quickly.

This method is done by a technician who will spray a cleaning agent on the carpet in order to loosen the dirt and dust in the fibers. Then a hot water/steam is sprayed on the carpet to help agitate the cleaning agent and further loosen the dirt and then it is sucked up by a wand via a high powered vacuum into a waste tank located outside on the truck mount.

With this method, it can take at least 4-24 hours to dry depending on the climate and humidity. Like the other cleaning systems I mentioned above, it can also become easily soiled again because of all shampoo residue left behind and you do have a risk of mold growth

Dry Steam or Steam Vapor – The dry steam or steam vapor method is by far the best and safest way to clean your carpets if it is done right with organic cleaning compounds and the proper HEPA vacuuming system. This technique was invented in 1980’s and there are several different cleaning compounds and various techniques that have been invented over the years that can make it much safer.

The dry steam method is done by first using a good HEPA vacuum to slowly vacuum the carpets. It is even a good idea to vacuum them twice. The next step is to apply an organic nontoxic, biodegradable cleaning compound on the carpet using a rotary floor machine/scrubber to loosen the fibers and dirt. The idea is that this cleaner and the scrubber act as micro-sponges so they can effectively scrub and loosen the dirt and cleaning compound in the carpet so it can then be removed thoroughly with a high-powered HEPA vacuum.

This method is best mainly because it does not wet and soak the carpets which can cause water damage, mold and ruin the carpets. It also dries the quickest, sometime in 1 hour or less which is great for homes with a lot of foot traffic and commercial enterprises that need to stay open. In addition, it has been proven as the best method to reduce dust and allergens in the carpet.

My statements are also backed by science.

But before I get into the science, let me first disclose that this is not the best method to have the cleanest looking carpets. If your goal is a cleaner look, then this method may not be the best because it doesn’t clean as deep as other methods. But if your goal is to have a safe cleaning process that uses no toxins, creates no water damage and does not create a perfect moist environment for toxic molds and bacterias to grow, then dry steam with HEPA vacuum is by far the safest!

The Science

For example, a 2008 study found that a household vacuum cleaner equipped with a high-efficiency particulate air (HEPA) filter and a dust finder indicator, and a “dry steam” cleaner is one of the most effective methods to clean lead dust in your carpet. The researchers concluded, “slow and steady HEPA vacuuming with the help of a dust finder indicator reduces surface and overall lead dust in carpets, and dry steam cleaning further reduces surface lead contamination as compared with HEPA vacuuming alone.”

A 2009 study found that repeated HEPA vacuuming supplemented with dry steam cleaning was an effective method to reduce house dust mite (HDM) allergen concentration and loading in carpets. The results of the study indicated that both cleaning methods substantially reduced the loading of allergens as well as dust in carpets. (2)

In a 2014 study, researchers compared methods for removal of dust mites, dust mite allergens, and mold from the carpets. The carpets were artificially worn to simulate 1 to 2 years of wear in a four-person household. The worn carpets were inoculated together with a common indoor mold (Cladosporium species) and house dust mites and incubated for 6 weeks to allow time for dust mite growth on the carpet. The carpets were randomly assigned to one of the four treatment groups.

Researchers found that the steam vapor (dry steam) treatment demonstrated the greatest dust mite population reduction (p < 0.05) when compared to other methods. The steam-vapor treatment effectively killed dust mites and denatured dust mite allergen in the laboratory environment.(3)


  1. Cleaning efficacy of high-efficiency particulate air-filtered vacuuming and “dry steam” cleaning on carpet
  2. Evaluation of HEPA vacuum cleaning and dry steam cleaning in reducing levels of polycyclic aromatic hydrocarbons and house dust mite allergens in carpets
  3. Inactivation of dust mites, dust mite allergen, and mold from carpet


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